Fig. 1

The FLT3-ITD⁺ MOLM-13 cells and primary leukemic stem cells are sensitive to the combination of RA, Btz and ATO. A MOLM-13 AML cells were treated for 72 h with 10nM RA, 2.25nM Btz, and 500nM ATO, alone or in combination. In all the figures retinoic acid is indicated as R, bortezomib as B, and ATO as A. Cell death was assessed by propidium iodide (PI) exclusion assay, analyzed by flow cytometry (one-way ANOVA). B Cell cycle analysis of MOLM-13 cells 48 h after treatments as in (A). The cells treated with BA show an increased percentage of subG1 phase relative to C cells but only those treated with RBA exhibit significant modulation of all the cell cycle phases. (the asterisks refer to two-way ANOVA analysis of each sample compared vs RBA, and colors are in accordance with the corresponding phase of the cell cycle; § indicates two-way ANOVA analysis of subG1 BA vs subG1 C: P < 0.005). C MOLM-13 cell morphology analyzed by Wright-Giemsa staining, 72 h after treatments. D FLT3-ITD⁺ CD34⁺ cells, isolated from patients at diagnosis (n = 5 upper panels) or from healthy volunteers (n = 3 lower panels), were treated ex vivo for 96 h with 10nM RA, 3nM Btz, and 500nM ATO, alone or in combination. Cell death (left) and cell density (right) were measured by flow cytometry after staining with PI (one-way ANOVA)